Millennium Seed Bank FAQs

Kew's Millennium Seed Bank - frequently asked questions

See below for commonly asked questions about Kew's Millennium Seed Bank. If you don't find what you're looking for here, try the search box situated at the top right of this page or check out our recommended links.

Seeds and species

Can I request seeds from Kew's Millennium Seed Bank?

Two seed lists are available. Seeds are sent out to registered customers for use in research or restoration.

One list relates to supply for general non-commercial research and trialling by organisations. The other relates to supply for research, breeding and training by organisations regarding food and fodder production, in respect of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). There are instructions in English, French and Spanish. Please note that we are unable to accept seed requests from private individuals and will not normally be able to reply to such enquiries.

We would be interested to hear from organisations making seed collections from wild plant populations that might wish to send seed for long-term conservation.

The criteria for accepting samples are that they:

Have been collected legally (with appropriate permission from both landowner and government) and, if imported, that this has taken place legally (ie that plant health and CITES legislation has not been contravened).

Are of wild provenance.

Are in reasonable quantity (small collections of a few hundred seed, particularly from non-endangered populations, cause many processing and maintenance difficulties).

Are recently harvested (collections that are more than a month or two old may well be dead).

Are well documented and include at the very least, date collected, collector(s) and accurate location (preferably with a map reference or latitude / longitude) and, ideally, sampling, ecological and other data.

How many species are held in Kew's Millennium Seed Bank?

As of 14 March 2014 we have in total:

34,088 wild plant species

1,980,405,036 seeds in storage

How can I germinate seeds from my garden?

If recently harvested, filled, mature seeds have been placed on damp but not waterlogged compost and provided a little warmth, and they still won't germinate, the most likely causes are either inappropriate environmental conditions (particularly temperature and light) or dormancy.

The conditions required for germination, although partly genetically determined in many cases, are strongly influenced by the environment under which the seeds developed. Two seed-lots of the same species may behave in quite different ways. This said, with a little detective work and some experimentation, it is often possible to increase the likelihood of successful germination.

The most important thing to consider is whether the seeds have a hard seed coat or some covering structure that might prevent water uptake or physically inhibit germination. If so, they may need to be scarified. Filing through the seed coat with a narrow file until the contents are just visible may be possible with larger seeds. Smaller seeds might be gently rubbed within a folded piece of fine sandpaper.

The next thing to consider is the ecology of the species. Where does the species naturally occur in the world and at what altitude? For instance, seeds of many temperate species that are programmed to germinate in the spring often respond to a period of moist chilling. After scarification (if appropriate), the seeds can be placed on wetted tissue paper inside a reasonably airtight container and left within a refrigerator (+ 4°C) for up to three months. The moisture should be checked occasionally. Alternatively, the scarified seeds could be placed in or on moist compost and left within a cold-frame over winter. Following this treatment, the seeds can then be germinated on moist compost and in the warm as usual. Many small-seeded species need exposure to light for germination and also benefit from experiencing temperature fluctuations each day. This is an adaptation to prevent germination until the seeds are brought to the soil surface by disturbance.

If none of the above work, it might be necessary to try different germination temperatures. Unfortunately, the temperature range over which seeds germinate may change as the dormancy status of the seed changes.

The Seed Information Database (SID) provides germination data on seed lots that have been successfully germinated by the Millennium Seed Bank. This may help provide a number of clues.

How can I collect and store seeds from my garden?

Taking care during the collection of seed can make a huge difference to its storability.

Collecting before the seeds are fully ripe may mean that the seed is incapable of surviving drying. Where dry seed capsules are involved, the ideal harvest time is usually when the seeds are on the point of being shed eg when a seed capsule first splits. In the case of 'wet' fruits containing seeds, the ideal harvest time is when the fruits are fully ripe, and therefore attractive to mammals and birds. Quite often, fruit ripeness is indicated by a change of colour. Seeds that are very soft or that are green are usually not ripe. Where a range of seed colours is present on the plants, some indication of which seeds to harvest can usually be worked out by looking for those seed colours that equate to seed hardness.

Unlike most seed collecting for conservation that involves random sampling, gardeners may wish to be selective of the individuals to be harvested. This will increase (though not guarantee) the chances that some of the individuals in the next generation possess similar characteristics to those selected. Sexual reproduction results in a shuffling of the genetic variation present in the previous generation. Consequently, the greater the size of the next generation raised, the greater the chances of the desirable characteristics being found. Furthermore, F1 hybrid varieties will not breed true; these will need to be purchased afresh each season.

Sensible precautions should be adopted when handling all seed and fruits because some are poisonous. All such material should be kept out of the reach of small children. Seeds borne within fruits need to be extracted. This can be done by scraping the seeds onto a colander or sieve followed by washing to remove pulp and juice. Sometimes after extraction, the seed is covered with a mucilaginous layer. If the seeds are spread out and left to dry, this mucilage can usually be rubbed off. Similarly, obviously empty, damaged and poorly-developed seed, plus debris, is best removed from other seed collections prior to drying and storage.

Harvested seeds need to be dried if they are to be stored. Note that this will only be true for orthodox (desiccation tolerant) species. Most garden plants grown in temperate regions will have such seed.

Drying seed shares many of the same principles as drying clothes. The one difference is that seeds (and particularly moist seeds) should never be exposed to high temperatures (and certainly not above 40°C) if they are to be kept for any length of time. Seed batches will dry most rapidly and furthest if spread out in a dry place where there is some air movement. If it is necessary to keep the seed in bags for drying, use non-glossy paper bags that allow moisture to pass out. Do not use plastic bags. An alternative drying method is to place the seeds for up to two months inside a relatively airtight box above a layer of fresh silica gel using a ratio of gel to seed of about 3:1. Carefully follow the supplier's directions when using silica gel. Alternative drying agents include oven-dried rice. An ideal way of drying seeds from the garden is to use the mini seed bank.

When the seeds have been dried they should be kept dry by being placed within an airtight container. Lever-lidded fruit preserving jars with rubber gaskets are usually excellent because they seal well and have a wide opening. Certain other types of readily available container may also be sufficiently airtight. Once dried, packaged and labelled, the seeds can be placed in a cool location. Domestic refrigerators are good though the seeds should be well separated from food and kept out of the reach of small children. When seeds are required, let the container warm up and dry off before opening. Then re-close as quickly as possible. It may be advisable to let the seeds pick up moisture from the air for several days prior to sowing, scarifying them first, if necessary.

Is it all right for me to collect seeds for my garden when I'm abroad?

The collection and export of seed from most countries is covered by their national legislation.

Seed collecting is covered by national legislation in most countries. Import of seed into the UK is covered by quarantine restrictions. Endangered species are covered by international legislation (CITES).

Our collectors and collaborators abroad are experienced at working within these rules. To avoid breaking laws and harming wild plant populations, please do not collect and bring back seed yourself. Enjoy the plants where they grow!

Over-collection of plants can lead to them becoming endangered.

Can all seeds be stored?

Storable seeds are those that can dry and not die. Drying is lethal for most organisms including mature plants. However, many seeds are tolerant of drying (desiccation-tolerant). When dry, seeds age slowly, but they will eventually die with time. Dried seeds can however also withstand freezing. When placed at sub-zero temperatures, the ageing process is further slowed down.

Species with desiccation-tolerant seeds are classified as ‘orthodox’. It is these species that we store in the Millennium Seed Bank (MSB).

Species bearing desiccation-intolerant seeds are termed ‘recalcitrant’. Because they cannot be dried, they cannot be frozen for conventional long-term storage. This is because, on freezing, the water in the cells turns to ice, which destroys the plant cells.

Dried and frozen seeds of orthodox species can live for tens or even hundreds of years. By far the majority of plant species studied are orthodox. However, the remainder are recalcitrant or intermediate between recalcitrant and orthodox in behaviour. Such species cannot be stored in the MSB. Research work is being carried out to determine why these differences exist and to explore the optimisation of cryopreservation for the long-term storage of these species.

How long can seeds live?

The life of a seed varies according to the species and the conditions it has been stored in.

There are many stories of the germination of seeds removed from ancient Egyptian tombs. To the best of our knowledge, none of these stories is strongly supported by archaeological evidence of the antiquity of the seeds. This aside, the conditions within Egyptian pyramids are very dry and would permit seed longevity in certain species to extend to thousands of years. Nearly all of the records of extreme longevity relate to seeds with hard coats (or testas).

Seed viability has been modelled for some 70 species and it is possible to predict their longevity, given moisture content, temperature and initial germination.These models have been developed by rapidly ageing batches of seeds at a range of high moisture contents and high temperatures, and then plotting their loss of viability. Extrapolation (often a risky procedure) to viability loss under more favourable storage conditions suggests that, for instance, mung beans might live for nearly 24,000 years, and the African grass, teff (Eragrostis tef), could live for 15,000 years.

Not surprisingly, few longevity experiments of any age that mirror seed conservation storage are available for us to study today. However, in 1987, samples of cereal and weed seeds were germinated that had been placed within sealed glass vials in Vienna 110 years earlier (reported by Steiner & Ruckenbauer in 1995). One of the aims of the Millennium Seed Bank Partnership is to set up a carefully controlled set of longevity experiments that future generations can study.

Although the seed viability equation predicts survival for hundreds to thousands of years under gene-bank conditions (15% RH, -20°C), there are only a handful of credible reports of seeds actually surviving for more than 150 years. Recently we have conducted germination tests on seeds of 33 South African species collected in 1802/3. The seeds were found at the National Archives in London among the papers of a Dutch merchant, Jan Teerlink, whose ship was captured by British privateers during its return from the Far East via the Cape of Good Hope, South Africa. Seeds of three species germinated: two legumes (Liparia sp. and Acacia sp.) and a Proteaceae (Leucospermum sp.). Our report in Seed Science Research (reference below) of seeds surviving for over 200 years (supported by carbon-dating) under sub-optimal conditions, suggests adaptation for extreme seed longevity in species of seasonally dry, Mediterranean environments.

Other examples of extreme longevity include a seed of Canna compacta that was reported to be germinated following extraction from inside a radio-carbon-dated 600 years old ceremonial rattle made of a walnut (Juglans australis) shell. Even older longevity has been reported in a seed of the Indian or sacred lotus Nelumbo nucifera from an ancient lake bed in China. This seed has been germinated and subsequently radio-carbon-dated by Shen-Miller and colleagues in California as being 1,288 ± 271 years old. An interesting story relates to seeds of the legume Albizzia julibrissin on a pressed herbarium specimen collected from China in 1793 and deposited in the British Museum. This specimen was 'watered' while a fire was being extinguished in 1940 and several seeds (at least 147 years old) germinated.

Seed longevity in the soil is also well known to gardeners. In regions where the soil retains a high level of moisture, most (non-hard-coated) seeds will survive in a hydrated state, not in a dry state as in seed stores. For them to survive in this wet state they must be able to respire and must possess dormancy that prevents germination. In 1879, W.J. Beal, in Michigan, buried samples of seeds of 23 species in moist sand as an experiment in soil 'seed bank' longevity. Seeds of the moth mullein (Verbascum blattaria) from this experiment germinated in 1970.

I am looking for vegetable seeds can you help?

The Millennium Seed Bank Partnership specialises in collecting and storing seeds from wild plant species only.

Although many of these are the wild relatives of modern-day crops, we do not hold vegetable seed collections in the bank. In the UK the Heritage Seed Library run by Garden Organic safeguards rare vegetable varieties.

Images and artists

Can I use an image from the website or can you provide me with a seed conservation related image?

Kew has an online image library 'Kew Images'. This is an extensive library of photographic and botanical art collections, historic archives and publications available for licensing and download. The Press Gallery has themed collections of photographs illustrating Kew’s work in the UK and around the world.

I am an artist and want to use seeds as subjects for my work, can you help?

If you are working for the Press

If you are an artist or photographer working for the Press, please contact Kew’s Press Office at pr@kew.org in the first instance.

If you are an independent artist

The many commitments of staff at Kew's Millennium Seed Bank mean that we have only a limited amount of time for direct collaboration with artists and providing seeds for art projects. However, we ourselves are constantly delighted and inspired by the enormous variety of form shown by seeds and fruits and we want to do as much as possible to give artists access to that diversity.

Using seed images for inspiration

You may use the images as inspiration for private artwork, but please remember, all of the images are the copyright of the Board of Trustees of the Royal Botanic Gardens, Kew and you are not permitted to use them for anything other than private study (which would include making pictures of the seeds for your own personal enjoyment). Please also see the Terms and Conditions of Use of Kew's website, which sets out the permitted uses of the images. You may not use the images as the basis for art which is used in any kind of commercial context, for example, which is included in a book or which is displayed in a public exhibition, unless you have agreed a specific collaboration with us in advance.

Moreover, we would not hold these seeds in our collection, nor be able to work on them, without the co-operation of our network of partners around the world. Please give appropriate acknowledgement in any presentation of your work, both of Kew, and our partners in the Millennium Seed Bank Partnership. The source of seed is given on each image.

The images in the gallery are a selection from a growing number of digital photographs of seeds, arising from studies on the collections by our Seed Morphologist, Wolfgang Stuppy and his team. These are published on this website, via our Seed Information Database. It is not particularly easy to browse the full set of images in SID (hence we have made the gallery).

Come along to special events

In addition, once a year at 'The Big Draw' event, seeds are made available at Kew's Millennium Seed Bank for use by the public. This usually takes place in October. There may be other similar opportunities at other times during the year.

Other organisations of interest

Before approaching us about closer collaboration, please familiarise yourself with the procedures and requirements of organisations such as The Wellcome Trust, National Endowment for Science, Technology and the Arts and The Calouste Gulbenkian Foundation, all of whom have supported ‘sci-art’ and/or ‘artist in residence’ projects in the past. We would need a similar level of preparation before we could consider any application, and preferably firm ideas on potential funding.

Examples of completed works

We have had a very successful collaboration with Prof Rob Kesseler from Central Saint Martins College of Art and Design in London, which, to date, has led to the publication of three popular scientific books: Seeds - Time Capsules of Life, Fruit – Edible, Inedible, Incredible and The Bizarre and Incredible World of Plants. Our palynologist colleague, Madeline Harley, was also involved in the last of these. These books are innovative 'Sci-Art-Adventures', as well as being illustrated popular-scientific natural histories of seeds, fruits and pollen, are based upon and woven around the Millennium Seed Bank Project, and thus promote both the artists' and our own work.

The artist and gardener Francoise Sergy has recently created a computer animation and web project featuring five common plants of the UK and the work of the Millennium Seed Bank, entitled 'Hop, Stock and Bent'.

Sophie Munns was the 2010 Brisbane Botanic Gardens Artist-In-Residence at Mt Coot-tha, Brisbane. The residency focused on the extraordinary regional and global seed heritage - the critical work of seed conservation and the future of seeds - coinciding with the 2010 International Year of Biodiversity. Sophie visited the MSB in October 2011 and you can see her work on her blog 'Homage to the Seed'.

Accessing Seed Information Database images

Tick the small tick-box towards the bottom of the page on the right, labelled 'Morphology'; don't enter anything in any other box.Press 'Search' and SID will return a list of species for which we have recorded morphological data, including images - indicated by 'Morph' in pink type at the end of each record. This could be a bit slow, please be patient.

To view the images for each, click on the link (blue-underlined) for each record and SID will return all the data for that species.

Scroll down towards the bottom for the morphological data and at the botom of that section you will see the links to the images, with names like 'S-LS' (short for 'seed - longitudinal section'), for instance, indicating the image orientation.

Click each of these in turn to download the images. These images are only at low resolution, primarily intended for screen display. If you need a particular image at higher resolution, please contact us at msbsci@kew.org.

How do you capture the seed morphology images?

Digital image capture is via a Zeiss Axiocam HR system.

For small seeds the axiocam is mounted on a Zeiss Stemi SV11 stereomicroscope, with ring and sub-stage lighting provided by Schott KL 1500 sources.

For larger seed and fruits we mount a manual focus Nikon 55mm macro lens on the Axiocam camera, using them in conjunction with a Kaiser illuminated copy-stand (effectively a desk-top, or mini studio), which has fluorescent strip light sources above and below. For larger seeds and fruits we are also using a digital SLR (Nikon D700) and 60mm macro lens, together with the Nikon R1 lighting system.

What do you use to take the X-ray images?

X-rays are taken using a 'Faxitron' digital X-ray machine.

The seed samples to be X-rayed are laid out in Petri dishes or plastic grids with machine-punched holes set in a regular pattern, backed with waxed paper.

The X-rays are generated using very low voltages (much lower than are used for most medical applications) and the method is thus safe with the appropriate precautions. However, because there is a very small risk of genetic damage, the sub-sample is either discarded or used for germination testing.

How can I find work with the Millennium Seed Bank Partnership?

Vacancies will be advertised online. See Kew's main job page for current opportunities.

We also have many volunteers who are a valued and integral part of the Millennium Seed Bank Partnership, playing an important role in supporting our work. All vacancies for volunteers will be advertised on the volunteer opportunities page.

A limited number of short work experience placements are available each year to secondary school students.

Who else is doing this kind of work?

Most other seed banks around the world are concerned with conserving seeds of crop species.

A visit to the Global Crop Diversity Trust, Bioversity International and FAO websites (links found below) would help you to find out more about crop seed conservation. The Millennium Seed Bank Partnership (MSBP) has links to all three organisations and many crop seed banks. It is also a partner with the GCDT on the conservation of crop wild relatives.

In the UK, the UK Plant Genetic Resources Group draws together all of the agencies that are active in plant genetic resource conservation and use. The MSBP is represented on this group. A valuable source of UK information is the UK's Information Portal on Genetic Resources for Food and Agriculture.

There is an increasing interest in the ex situ storage of the seeds of wild species and new partners join the Millennium Seed Bank Partnership annually. Information about the activities of the many MSBP partners can be found on our partners page. In Europe, the MSBP is part of the European Seed Conservation Network (ENSCONET) which collaborates on the seed conservation of the European native flora.

Many countries have seed banks storing forest tree seed over the short-term. Some of these are MSBP members.

General information

I am an architecture student. Do you have any information about the building?

Kew's Millennium Seed Bank was designed by the London-based architects Stanton Willliams. An important aspect of the brief was that the design of the building was in character with its location at Wakehurst. Stanton Williams created a low-level building with barrel-vaulted roofing, inspired by the surrounding landscape forms. The main materials used for the external walls and roof were fair-faced concrete, sand-blasted to expose the aggregate in specific areas, York stone, painted steel and structural glass panels. The building has been designed to maximise energy conservation, while providing the best possible conditions for seed storage.

How is the Millennium Seed Bank Partnership funded?

In the mid-1990s, Kew secured large grants from the Millennium Commission and the Wellcome Trust to initiate a project to collect ten per cent of the world's wild seed-bearing plant species. This first phase was called the 'Millennium Seed Bank Project'.

Alongside donations from individuals, private foundations and companies, this funding enabled the construction of the Wellcome Trust Millennium Building and the development of global partnerships to safeguard one in ten of the world’s flora.

We are very grateful to all the individuals and organisations that supported the Millennium Seed Bank Project during its first phase (1995 – 2009). The project has now been renamed as the Millennium Seed Bank Partnership to reflect the extensive work undertaken by our partners and contributions from other organisations.

This second phase of the project still requires further funding to achieve its target of saving 25 per cent of the world's plant species by 2020.

How should I cite the website?

As this website was a collaborative work by project members please cite it as follows: